


What They Don't Know

by ravyn_nevermore



Series: OT3: Gunpowder and Genius [1]
Category: Sherlock (TV)
Genre: Demisexual Sherlock, F/M, Fantasizing, John Watson is a piece of shit, John and Mary are divorced, M/M, Masturbation, Multi, Other, Sapiosexual Jim, Sapiosexuality, Sexual Fantasy, Sherlock and Jim are married, Threesome - F/M/M, Vaginal Fingering, clitoral stimulation
Language: English
Status: Completed
Published: 2017-03-20
Updated: 2017-03-20
Packaged: 2018-10-08 03:06:17
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,893
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10376466
Author URL: https://archiveofourown.org/users/ravyn_nevermore/pseuds/ravyn_nevermore
Summary: Mary has a secret she's been harboring since even before she and John divorced. Should she tell them? What they don't know won't hurt her.





	

**Author's Note:**

> Ahoy!   
> In this canon-divergent AU, Jim and Sherlock are married. Mary didn’t die: she found out about John’s infidelity- Sherlock and Jim (who has warmed up to her; she’s always liked him) told her- and kicked him out, keeping Rosamund with her. As Sherlock and Jim have adopted an infant daughter- too small still for her own crib and sleeping in a bassinet in the nursery instead, Rosamund sleeps there for the night. This is a bit of a fix-it fic. John’s downward spiral since Season Three (abuse and infidelity) has been inexcusable. I hate the bastard. I am still grieving the loss of Mary: my flower, my queen, my goddess. And this is also a bit of a delve into my OT3. The only time I consider Jim to be not-gay is when it comes to this OT3.   
> If at any point you become confused, Mary’s left is Jim (since he is left-handed) and Mary’s right is Sherlock.   
> I do hope that you enjoy. Please remember that comments are a fic author’s paycheck and greatly appreciated. Fic, ho!

The sofa in the living room of the Kensington maisonette was surprisingly comfortable to lie on. Maybe it shouldn’t have been so surprising given the taste of the Irishman who owned it. The living room seemed smaller since they had moved the piano into it in order to turn the second bedroom into a nursery. Mary had visited dozens of times, but this was her first stay overnight. They’d given her spare pillows and a lovely spare duvet that were more than she could have asked for: she shuddered to imagine the price tag. The silence that hung in the air seemed as crisp, clean, and comfortable as the rest of the home. Just as there wasn’t a speck of dust, there wasn’t a sound to cut through the air. Mary thought she felt as if she were staying in a hotel, perhaps, but it was too clean and too quiet even for that. It was like staying in one of those resorts one often sees in a travel magazine. Straight off the page. She smiled to herself, reflecting on Jim’s insistence that she stay so she wouldn’t feel so alone. He really had warmed up to her over the months. She’d even go so far as to say he liked having her around. She turned to her side and closed her eyes, planning to sleep.

“...Mary…” The blonde’s ears perked at her name amongst unintelligible whispers. She opened her eyes again and looked around. She was still alone in the living room. She sat up, listening hard, trying to decide whether she’d imagined it.

 

  
Sherlock and Jim were trying to stay quiet, guessing that she might already be asleep and not wanting to wake her. “Jim, what if Mary hears us,” Sherlock had asked in a whisper, not knowing that the former Mrs Watson’s name had carried into the living room.

“Mm. You know I don’t mind an audience. You know I encourage the thrill of being caught. Besides, I think we both know she’d like it if she heard us.” Jim kissed the expanse of his husband’s neck slowly. “I bet she’s out there, straining to listen, touching herself slowly… anticipating… imagining…”

Sherlock bit his lip, thinking it over. Yes, the idea of someone listening was exciting. Almost as exciting as the idea of someone watching. “You’re right,” he whispered, submitting and getting himself lost in the way his and Jim’s bodies moved together.

 

 

Soft moans were soon heard coming from the master bedroom in the back. Mary blushed almost immediately, her whole face growing hot. She licked her lips and settled down under the duvet, unsure what to do. She supposed she could just ignore it… But the first time they’d stayed on her pull-out sofa bed- the night she kicked John out, they hadn’t been quiet either. She couldn’t help herself that night. She’d ended up with the blankets around her ankles and both vibrators inside her with the daydream of being caught between two of London’s most brilliant and dangerous men. She hadn’t orgasmed like that in… ever.

When she’d married John and he had become selfish in the bedroom, Mary too often resorted to faking her orgasms and using her toys while she was home alone. It was more satisfactory than anything her husband was failing to give her. Her mind wandered, but her fantasies always came back to Sherlock: bold, daring, brilliant, clever, dangerous Sherlock. She had begun having real orgasms again when John would bed her, but only as long as she kept the image of Sherlock in mind: vivid and compelling.

When Sherlock revealed that he was dating Moriarty, naturally he was added to Mary’s little fantasies. He was just as clever and bold as Sherlock, but more dangerous as well as charming, suave, and genteel. The three of them together would be unstoppable, Mary knew. Certainly, they knew it too. And the things they could accomplish in bed… It was no wonder Mary thought the ultimate revenge for her husband’s infidelity would be allowing him to discover his wife in bed with his best friend and his worst enemy. It was a fantasy that she was certain would never come true, but it thrilled her to her core.

Mary couldn’t help the arousal that bloomed as she listened to Jim and Sherlock entangled together in their marriage bed. She imagined the way they must move together, no doubt made for each other in more ways than one. Sherlock must look absolutely gorgeous being completely vulnerable to his darker, more powerful lover.

Mary bit her lip and moved her hand into her sweat pants, ghosting her fingertips over her milky thigh, wishing instead it was that of one of the men she was eavesdropping on. Likely, it would be Jim. Sapiosexual, seasoned James Moriarty who had an impressive knowledge of the human body and how it functioned. Sexual, sultry Jim who treated sex like it was an experience, a performance, an art instead of just a pastime at the end of the night. He would take charge and teach Sherlock anything and everything he knew about pleasing a woman.

Sherlock. Dear, sweet Sherlock who exuded sex appeal even to those who believe this demisexual, demiromantic man to be asexual. Virginal, innocent Sherlock… or so it seemed to those who didn't know him. Most would assume the proud and cocksure detective to be sexually demure, but it didn't seem quite that way. According to body language shown during his relationship with Jim, he was just as confident behind closed doors. Mary was certain that a night with them would be burned into her memory, not easily forgotten. She would emerge from that human plait a changed woman.

Perhaps Sherlock's dextrous hands would explore her breasts- plump from breastfeeding and pregnancy- the way she did now on herself. She teased her own nipples into firm, eager buds and wondered if Sherlock's violinist fingers would do the same: pinching and rolling just the way she liked. Her breath hitched and she tried not to make a sound, unwilling to be caught by the men she could hear in the midst of pleasure just down the fall. The very men she was fantasizing about.

Would they kiss her? Talk? Mary hoped so. On one side of her, smooth skin and soft, plush lips with a sinful baritone whispering the sweetest promises. On the other side, thinner lips framed by the scratch of stubble, breathing wicked phrases in a language she didn't quite understand.

Heart pounding, Mary shifted just enough to pull her sweats down, spreading her knees and lying back. The hand on her thigh- the one she dreamed could someday belong to Jim- moved inward, (re)acquainting itself with the pattern of her pubic hair and the shape and size of her labia, beginning to spread her wetness. She swallowed down a groan and parted her thighs more. Her middle finger dipped into her wet center and moved slowly upwards, encircling her clitoral hood again and again, coaxing the bundle of nerves out. She applied just a bit of pressure to her clit and pleasure crackled through her nerves like raw electricity. A moan fell from her lips, but she barely noticed.

The blood pounding in Mary’s ears and through her veins practically drowned out the muffled moaning of the married couple, but it hardly mattered anymore. That had just been the kindling. The fire was burning strong and hot with her vivid fantasy in which Jim slowly pushed two fingers inside of her with ease. She was soaking wet and probably leaving a mark on the couch. It didn't matter. She lifted her hips and pushed her fingers in deeper, curling them back to reach the sweet spot. Her mouth fell open and another moan left her throat, but again she barely noticed. If her fantasy were real, they'd have her crying out so loudly, they'd tell her to shush before she woke the neighbours.

Mary worked her fingers slow and deep, still arching off the couch. Jim was a man of precision and patience. He would keep her on edge as long as possible. Her nerves were singing, her mind blank except for the daydream, and sweat clung to her every pore.

Sherlock's hand would finally leave her breasts and ghost over her stomach- stopping to trace and admire the stretch marks left behind by her pregnancy-moving to her thigh. He'd tease the sensitive flesh of her inner thigh, gradually moving inward. Just as Jim would add a third finger, Sherlock would tease her clit, which throbbed in time with her erratic pulse. She wasn't sure she was breathing anymore. She closed her eyes and gave in to the fantasy and sensation.

If she was lucky, Sherlock would bend and explore her breasts and nipples with his lips and tongue, leaving only to kiss her neck or mutter sweet things into her ear. Perhaps Jim would remove his third finger and guide Sherlock to slip two fingers in beside his. Maybe they'd move opposite each other so Mary was never empty. Maybe they've move together, filling her and then leaving her wanting. Either way, she'd moan constantly, whispering first one’s name, then the other’s. They knew how to make her feel like a queen, more than any man- especially John- made her feel in the past.

As they gradually would speed up together, Mary would move her hips eagerly to match their rhythm the way she was doing now. They'd take turns teasing her clit with their thumbs. She was so close. So unbearably fucking close.

  
No longer could Mary hear them moan. She'd completely missed the sound of Sherlock's orgasm, as invested as she was in her own little dream world. The two lay together, quietly trying to catch their breath and basking in a post-coital cuddle.

“Jim… oh-- Sherlock,” Mary whimpered, unaware that _they_ could hear _her_ now. Finally, pleasure shattered the darkness behind her eyelids and she nearly saw stars. She cried out as she came hard, wetness soaking her fingers and thighs. Her whole body twitched and throbbed and it was so intensely incredible that it was almost painful.

Mary clung to the fantasy as she started to come down from the high of orgasmic bliss. They would spoil her, pulling their fingers out and taking turns to lick her clean, enjoying the flavour of her orgasm. In her post-orgasmic haze, she would watch them turn and kiss each other passionately, sharing the taste of her wetness in each other's tongue. They'd lie beside her and wait patiently for her to catch her breath, knowing that when she did, she was eager to pleasure both of them. They each would come twice before they slept; Mary would probably come three times. After all, they did love each other so. For now, she drifted to sleep, feeling content even if it was all in her mind and not at all possible.

Jim looked at Sherlock with a devilish smirk when they both heard Mary barely hold back the sound of her own orgasm. “I told you she was listening. I think it's time we talk to her, don't you?”

Sherlock thinks it over and nods. “In the morning. Over breakfast. Do you think she'll be surprised?”

“Pleasantly surprised, my dear. Pleasantly. Surprised."


End file.
